The present invention provides an improved casting alloy for use in jewelry and dentistry. Gold is generally alloyed with other metals for such use and requires a relatively low melting point. The alloys must be moldable and castable with a low surface tension to permit conformance to intricate molds. Such alloys should provide a material which does not easily corrode or tarnish, especially when used in jewelry, or in the field of dentistry.
It is basic that gold is one of the most valuable metals and the look of gold is a highly desired characteristic of any metal alloy.
In accordance with this invention, an alloy is provided which contains no gold, and yet which provides an alloy material that polishes, works and looks like gold. Also the alloy of this invention can be corrosion resistant in the manner of gold in a liver sulfate atmosphere, or even in the presence of hydrochloric acid. In the dental field, the preferred alloy of this invention may be finished in the manner of standard crown and bridge gold alloys
The alloy of this invention may resemble l0k gold in color and be highly corrosion resistant equal or superior to lower gold alloys, even though the alloy of this invention has zero percent gold.
In attempts of the prior art to develop a metal alloy possessing the true color of gold while maintaining its capabilities of being readily workable and polished, various non-precious metals and gold have been tried. For example, the present applicants' U.S. Pat. No. 4,350,527 is directed to a gold colored alloy having 0 to 10 percent gold content with 7 to 20 percent copper, 15 to 20 percent indium and 5 to 15 percent palladium. The alloy of '527 teaches 0 to 10 percent gold. However, '527 does not disclose the unexpected marked increase in gold color caused by the reaction of a copper and high indium content, combined with a high palladium content.